1. Field of the Invention
This invention relates to liquid crystal display apparatuses, and particularly to a liquid crystal display apparatus which includes a liquid crystal panel wherein a plurality of light receiving elements for detecting light are formed in a display region in which a plurality of pixels for displaying an image are disposed such that the position of a face of the liquid crystal panel with which a detection object physical body touches is detected based on light detected by the light receiving elements.
2. Description of the Related Art
A liquid crystal display apparatus is advantageous in that it is slim, light in weight and low in power consumption. Therefore, the liquid crystal display apparatus is used very much in electronic apparatus for various applications including mobile applications such as a portable telephone set and a digital camera.
A liquid crystal display apparatus includes a liquid crystal panel including a pair of substrates and a liquid crystal layer filled between the substrates. Typically, the liquid crystal display apparatus modulates light irradiated from a planar light source such as a backlight provided on the rear face side of the liquid crystal panel and transmits the modulated light therethrough. An image is displayed on the front face side of the liquid crystal panel with the modulated light transmitted through the liquid crystal panel.
The liquid crystal panel is, for example, of the active matrix type, in which thin film transistors (TFTs) which function as pixel switching elements are formed in a display region for displaying an image. When a potential is inputted to a pixel electrode, the corresponding pixel switching element varies the voltage to be applied to the liquid crystal layer to control the transmission factor of light to be transmitted through the pixel thereby to modulate the light.
Liquid crystal display apparatus have been proposed wherein a light receiving element is built in addition to a TFT which functions as such a pixel switching element as described above. For example, it has been proposed to form, for example, TFTs which function as light receiving elements on a TFT array substrate on which a plurality of TFTs which function as pixel switching elements are formed in an array. The liquid crystal panel just described is disclosed, for example, in Japanese Patent Laid-Open No. 2007-18458.
Where light receiving elements are built in a liquid crystal display apparatus as described above, since a function as a user interface can be implemented, the necessity to provide a touch panel separately on the front face of the liquid crystal panel is eliminated. Therefore, miniaturization as a user interface is facilitated. Consequently, the liquid crystal panel is called I/O touch panel (Integrate-Optical touch panel).
In the liquid crystal panel, light of an image of a detection object physical body such as, for example, a finger of a user or a touch pen which touches with the front face of the liquid crystal panel is detected by the built-in light receiving elements. For example, an opening through which light advancing from the opposing substrate side positioned on the front face side in an opposing relationship to the TFT array substrate toward the TFT array substrate side positioned on the rear face side is provided in a corresponding relationship to the light receiving region, and the light receiving elements are formed in a corresponding relationship to the opening. Thus, the light transmitted through the light receiving region is received by the light receiving elements. Thereafter, the position at which the detection object physical body touches with the liquid crystal panel is specified based on the light detected by the light receiving elements. Then, an operation corresponding to the specified position is carried out by the liquid crystal display apparatus itself or by some other electronic apparatus connected to the liquid crystal display apparatus. A liquid crystal display apparatus of the type just described is disclosed, for example, in Japanese Patent Laid-Open No. 2006-330578.